1. Field of the Invention
The present invention relates to vibrating gyroscopes and electronic devices including vibrating gyroscopes. More specifically, the present invention relates to a vibrating gyroscope for use in, for example, a camera-shake correcting device of a video camera, a navigation system, or other apparatus, and to an electronic device including such a vibrating gyroscope.
2. Description of the Related Art
FIG. 11 is a schematic perspective view showing the construction of a known vibrating gyroscope. In FIG. 11, a vibrating gyroscope 1 includes a vibrator 2 having a rectangular column shape which is made of a piezoelectric ceramic material, supporting members 3, 4, 5, and 6 which are made of a metal and which are connected to the vibrator 2, and a housing 7 to which the supporting members 3, 4, 5, and 6 are fixed. The housing 7 is made of an insulating resin and has a frame shape, and the supporting members 3, 4, 5, and 6, which extend along both sides of the vibrator 2 in the width direction thereof, are fixed to the housing 7 by insert molding, and the vibrator 2 is thereby retained at the central region of the housing 7. Portions of the housing 7 at which the supporting members 3, 4, 5, and 6 are fixed to the housing 7 are hereinafter called fixing portions 3a, 4a, 5a, and 6a, respectively. The vibrator 2 serves as a free—free beam which vibrates in the thickness direction thereof in the bending vibration mode. The supporting members 3, 4, 5, and 6 are disposed at positions near two nodes of the vibrator 2.
In the vibrating gyroscope 1, although the supporting members 3, 4, 5, and 6 are provided at the bottom side of the vibrator 2, in actuality, other supporting members are fixed between the vibrator 2 and the housing 7 at the top side of the vibrator 2.
In addition, the supporting members 3, 4, 5, and 6 may be constructed such that the supporting members 3 and 4 are integral with each other and the supporting members 5 and 6 are integral with each other.
In the vibrating gyroscope 1 which is constructed as described above, predetermined electrodes (not shown) are formed at the top and the bottom surfaces of the vibrator 2, and the vibrator 2 vibrates in the thickness direction thereof in the bending vibration mode when a driving signal is applied to the electrodes via the supporting members. When an angular speed around the longitudinal direction of the vibrator 2 is applied to the vibrator 2 while it is vibrating in the thickness direction thereof in the bending vibration mode, the vibrator 2 starts to vibrate in the width direction thereof in the bending vibration mode due to the Coriolis force. The amplitude of this bending vibration of the vibrator 2 in the width direction thereof is detected by Coriolis-force detection electrodes (not shown) provided on the vibrator 2 and is transmitted via the supporting members. Accordingly, the angular speed applied to the gyroscope 1 can be detected.
Similar to other common electronic devices, the size of vibrating gyroscopes must be reduced. However, since the Coriolis force applied to a moving member is detected in the vibrating gyroscopes, when the weight of the housing which contains the vibrator is reduced in accordance with the miniaturization, a problem occurs in that the degree of vibration transmission to the outside increases and the temperature drift also increases. In addition, since the supporting members are also used as electric wires for transmitting the driving signal to the vibrator and receiving a detection signal from the vibrator, the weight of the housing cannot be increased by forming the housing with a metal.